import deleteEmpty = require('delete-empty');

deleteEmpty('foo').then(f => f[0].toLowerCase());
deleteEmpty('foo', {}, (err, f) => {
    if (err) {
        err.message;
    } else {
        f[0].toLowerCase();
    }
});
deleteEmpty('foo', (err, f) => {
    if (err) {
        err.message;
    } else {
        f[0].toLowerCase();
    }
});

deleteEmpty.sync('foo')[0].toLowerCase();

(async () => {
    const deleted = await deleteEmpty('foo');
})();
